25th March 2010

Homeostasis

Definition
- Homeostasis enables living organisms to maintain equilibrium despite the change in the external environment

- Maintain equilibrium
- Living system
- Despite the change in the external environment

Processes
- Osmosis
- Diffusion
- Active Transport

Biomolecules

ENERGY, MATTER & ORGANISATION - BIOMOLECULES
Living systems are complex and highly organized, and they require matter and energy to maintain this organization.
  • Energy is stored in the organization of matter
- Energy is stored in fats in human beings.
  • Living organisms use matter and energy to build and maintain body structures
- Milk contains calcium that is used by young mammals to build bones. Proteins found in milk builds muscles in the body.
  • Living organisms obtain and process matter and energy
  • The structure of a molecule always dictates its function.
  • The structure and function of biological living systems obeys the laws of thermodynamics.
  • Communities of organisms depend on the cycling of matter and the flow of energy
- Water and Carbon Cycle
  • The constant flow of energy and cycling of matter in the biosphere leads to a balanced or steady state.

This balance is achieved through various biogeochemical cycles and the processes of photosynthesis and cellular respiration - focus is on ENERGY

The questions we ask about ourselves and the world around us:
  • Are we just chemicals?
  • Are we what we eat?
  • Why is the carbon molecule suitable for life as we know it?
- Because the carbon atom has a valency of 4 so it can bond with 4 other atoms and produce different types of
macromolecules each with different properties and functions.
- Carbon can combine with itself.
  • Why is the chemistry of water suitable for life

Energy
- Energy cannot be created or destroyed, but it can be LOST, like in heat.
- Change from one form to another form
- Flow from one system to another system
- Flow from one organism to another organism